The Experimental Study On Mechanical Property Of Bolted Joint With Glued Timber And Steel Plate

The reserve wood resources in China are abundant,while the domestic fast-growing wood resources are scarce,and the wood structural engineering materials mainly rely on imports.The research and application of modern wood structures are also behind those in developed countries such as Europe,America and Japan,so it is urgent for our country to enrich the theory and practical application of modern wood structure.With northeast larch glued wood and steel plate as research objects,this paper has studied the influence of thickness-diameter ratio,bolt spacing distance,staggered and parallel mode on mechanical properties of bolted connections respectively in order to provide basis for the future application of bolt connection in relevant wood structure.The main contents of this paper are as follows:(1)A variety of bolt connection failure modes were obtained by summing and analyzing relevant theory,and the calculation method of bearing capacity of bolted connections was deduced through various assumptions.(2)The material parameters were obtained by the material test,and the constitutive relation of the material was analyzed.The finite element model was established and the conclusions on mechanical properties of the multi-bolt connection were obtained.(3)The influence of thickness-diameter ratio on mechanical properties of bolt connection was analyzed through the thickness-diameter ratio test,and the results showed that the thickness-diameter ratio would affect the bearing capacity and change the bolt failure mode with the optimal thickness-to-diameter ratio 7.5?10;Combined with the calculating method of bolt connection at home and abroad,the connection calculating method of glued timber-steel plate bolt was deduced with well accuracy..(4)The influence of bolt spacing distance on bolt mechanical properties was analyzed through spacing distance test,and the results supported that the bolt spacing distance would improve the mechanical properties of bolt only within a certain range.The load-slip curve was fitted by Foschi formula and the applicability was good.(5)The influence of bolt distribution on bolt mechanical properties was analyzed through staggered and parallel test,and the results revealed that the number of bolt column would improve the mechanical properties of bolt connection,and staggered distribution of bolt could bear more loads with poorer ductility compared with parallel distribution.The conclusion of the finite element model was in consistent with the experimental result.